Turn a bare AssertionError into a real error message

httpie/cli/argparser.py

@@ -413,7 +413,20 @@ def _guess_method(self):
         """
         if self.args.method is None:
             # Invoked as `http URL'.
-            assert not self.args.request_items
+            if self.args.request_items:
+                # An optional argument sitting between METHOD/URL and the
+                # first REQUEST_ITEM splits the positional run in two, and
+                # argparse fills each run's slots independently: METHOD
+                # and URL end up absorbing the first run between them,
+                # leaving REQUEST_ITEM to catch whatever comes after the
+                # split, which is why method lands as None here even
+                # though a request item was given.
+                self.error(
+                    'METHOD, URL and REQUEST_ITEM all have to sit next to '
+                    'each other with nothing else in between; move any '
+                    'other arguments before METHOD or after the last '
+                    'REQUEST_ITEM.'
+                )
             if self.has_input_data:
                 self.args.method = HTTP_POST
             else:

tests/test_httpie.py

@@ -1,5 +1,6 @@
 """High-level tests."""
 import io
+import sys
 from unittest import mock
 
 import pytest
@@ -143,6 +144,35 @@ def test_form_POST_file_redirected_stdin(httpbin):
     assert 'cannot be mixed' in r.stderr
 
 
+@pytest.mark.skipif(
+    sys.version_info < (3, 13),
+    reason=(
+        "argparse only splits the positional run this way on 3.13+; "
+        "on earlier versions the same command is rejected upstream "
+        "with its own 'unrecognized arguments' error before _guess_method "
+        "ever runs, so there's nothing here for the fix to catch"
+    ),
+)
+def test_option_between_method_and_url_reports_a_clear_error():
+    """
+    https://github.com/httpie/cli/issues/1614
+
+    An option sitting between METHOD and URL splits the positional run
+    argparse sees into two, and on Python 3.13+ argparse fills each half
+    on its own: METHOD and URL absorb the first half, URL's real value
+    gets read back as a REQUEST_ITEM, and METHOD is left unset entirely.
+    That used to reach an internal assertion and crash with a bare
+    AssertionError instead of telling the caller what went wrong.
+    """
+    r = http(
+        'POST', '--auth-type', 'bearer', '--auth', 'token',
+        'http://example.org',
+        tolerate_error_exit_status=True,
+    )
+    assert r.exit_status == ExitStatus.ERROR
+    assert 'METHOD, URL and REQUEST_ITEM' in r.stderr
+
+
 def test_raw_POST_key_values_supplied(httpbin):
     r = http(
         '--raw',